package com.wxg.ch13;

import com.wxg.ch12.FileOperation;
import com.wxg.util.Res;

import java.util.ArrayList;

public class RBTree<K extends Comparable<K>, V> {

    private static final boolean RED = true;
    private static final boolean BLACK = false;

    private class Node {
        public K key;
        public V value;
        public Node left, right;
        public boolean color;

        public Node(K key, V value) {
            this.key = key;
            this.value = value;
            left = null;
            right = null;
            color = RED;
        }
    }

    private Node root;
    private int size;

    public RBTree() {
        root = null;
        size = 0;
    }

    public int getSize() {
        return size;
    }

    public boolean isEmpty() {
        return size == 0;
    }

    private boolean isRed(Node node) {
        if (node == null) {
            return BLACK;
        }
        return node.color;
    }

    public void add(K key, V value) {
        root = add(root, key, value);
        root.color = BLACK;
    }

    /**
     *
     *   node                    x
     *  /   \     左旋转        /  \
     * T1   x   --------->   node  T3
     *     / \               /  \
     *    T2 T3             T1  T2
     *
     * @param node
     * @return
     */
    private Node leftRotate(Node node) {
        Node x = node.right;

        // 左旋转
        node.right = x.left;
        x.left = node;

        x.color = node.color;
        node.color = RED;

        return x;
    }

    /**
     * 颜色翻转
     * @param node
     */
    private void flipColors(Node node) {

        node.color = RED;
        node.left.color = BLACK;
        node.right.color = BLACK;
    }

    /**
     *
     *      node                     x
     *      /  \      右旋转        /  \
     *     x   T2   ---------->   y   node
     *    / \                         /  \
     *   y  T1                       T1  T2
     *
     * @param node
     * @return
     */
    private Node rightRotate(Node node) {
        Node x = node.left;

        // 右旋转
        node.left = x.right;
        x.right = node;

        x.color = node.color;
        node.color = RED;

        return x;
    }

    private Node add(Node node, K key, V value) {
        if (node == null) {
            size ++;
            return new Node(key, value); // 默认插入红色节点
        }

        if (key.compareTo(node.key) < 0) {
            node.left = add(node.left, key, value);
        } else if (key.compareTo(node.key) > 0) {
            node.right = add(node.right, key, value);
        } else {
            node.value = value;
        }

        if (isRed(node.right) && !isRed(node.left)) {
            node = leftRotate(node);
        }

        if (isRed(node.left) && isRed(node.left.left)) {
            node = rightRotate(node);
        }

        if (isRed(node.left) && isRed(node.right)) {
            flipColors(node);
        }

        return node;
    }

    /**
     * 返回以 node 为根节点的二分搜索树中，key 所在的节点
     *
     * @param node
     * @param key
     * @return
     */
    private Node getNode(Node node, K key) {
        if (node == null) {
            return null;
        }

        if (key.equals(node.key)) {
            return node;
        } else if (key.compareTo(node.key) < 0) {
            return getNode(node.left, key);
        } else {
            return getNode(node.right, key);
        }
    }

    public boolean contains(K key) {
        return getNode(root, key) != null;
    }

    public V get(K key) {
        Node node = getNode(root, key);
        return node == null ? null : node.value;
    }

    public void set(K key, V newValue) {
        Node node = getNode(root, key);
        if (node == null) {
            throw new RuntimeException(key + " doesn't exist!");
        }

        node.value = newValue;
    }

    private Node minimum(Node node) {
        if (node.left == null) {
            return node;
        }

        return minimum(node.left);
    }

    private Node removeMin(Node node) {
        if (node.left == null) {
            Node rightNode = node.right;
            node.right = null;
            size --;
            return rightNode;
        }

        node.left = removeMin(node.left);
        return node;
    }

    public V remove(K key) {
        Node node = getNode(root, key);
        if (node != null) {
            root = remove(root, key);
            return node.value;
        }
        return null;
    }

    private Node remove(Node node, K key) {
        if (node == null) {
            return null;
        }

        if (key.compareTo(node.key) < 0) {
            node.left = remove(node.left, key);
            return node;
        } else if (key.compareTo(node.key) > 0) {
            node.right = remove(node.right, key);
            return node;
        } else {
            if (node.left == null) {
                Node rightNode = node.right;
                node.right = null;
                size--;
                return rightNode;
            }

            if (node.right == null) {
                Node leftNode = node.left;
                node.left = null;
                size --;
                return leftNode;
            }

            Node successor = minimum(node.right);
            successor.right = removeMin(node.right);
            successor.left = node.left;

            node.left = node.right = null;
            return successor;
        }
    }

    public static void main(String[] args) {
        System.out.println("Pride and Prejudice");

        ArrayList<String> words = new ArrayList<>();
        String filename = Res.root("pride-and-prejudice.txt");
        if (FileOperation.readFile(filename, words)) {
            System.out.println("Total words: " + words.size());

            RBTree<String, Integer> map = new RBTree<>();
            for (String word : words) {
                if (map.contains(word)) {
                    map.set(word, map.get(word) + 1);
                } else {
                    map.add(word, 1);
                }
            }
            System.out.println("Total different words: " + map.getSize());
            System.out.println("Frequency of PRIDE: " + map.get("pride"));
            System.out.println("Frequency of PREJUDICE: " + map.get("prejudice"));
        }
        System.out.println();
    }
}
